Since the early part of this century, the automobile has become a major part of the culture both in the U.S. and throughout the world. The independence, freedom, and rapid travel that automobiles provide, however, has also resulted in an individual becoming lost, involved in accidents, and becoming victims of crime. By way of specific example of the latter, when an individual traveling in a vehicle experiences mechanical failure, they encounter a potentially dangerous situation because of the high crime rate in an area or unfortunate random acts of violence which occur upon the freeway and road systems. Likewise, vehicle theft is an ever increasing problem with vehicles being stolen for personal use or parts. A new criminal trend has recently emerged known as carjacking wherein a vehicle is physically taken while being operated.
The prior art includes a number of systems which allow a vehicle's occupant to obtain assistance if such assistance is needed, or to track the vehicle in the event of theft. See, e.g. U.S. Pat. No. 5,043,736 to Darnell, et al., U.S. Pat. No. 5,223,844 to Mansell, et al., U.S. Pat. No. 5,557,254 to Johnson, et al. These systems all share the same basic concept, that is, placing global positioning system (hereinafter GPS) in a vehicle to transmit the received GPS signals from the vehicle to a monitoring center over a cellular telephone link or pager system network. These systems are comprised of various components. Some have a GPS receiver located in the vehicle. The GPS receiver obtains GPS signals from satellites in orbit around the earth and, upon obtaining these signals, uses signal processing techniques to determine the GPS receiver's location. Also located in the vehicle is a communication device to transmit the GPS signal from the vehicle. These communication devices include cellular transmission systems, pager systems or radios. Finally, a base center or monitoring center receives the GPS signal from the vehicle, and processes the information to determine the position of the vehicle. However, each of these prior art systems has significant drawbacks relating to both the manner in which they provide verbal communication between the operator of the vehicle and the monitoring center and the manner in which the GPS data is transmitted between the automobile and the monitoring center.